Build Recurring Income

My after tax income (including bonus and interest income) is approximately US$325K per month. I am a professional and my job is relatively steady (been with the same company for more than 5 years). What percentage of my after tax income should I be saving (either for retirement or a rainy day)? Obviously, it is better to save as much as possible. But I guess I want to know what percentage is a prudent guideline. Thanks

Im 25, I am in shock when i see my friends (same age, same entry level income) go out and buy 250k-300k houses like its nothing. They dont have 20 bucks to fill up the gas tank but they can afford 250k house??? I dont want to be in their position where 90% of their income goes to mortgage, without having any savings on hand. what is a proper mortgage payment/income ratio?